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SDL-MCP (Symbol Delta Ledger MCP Server) is a cards-first context system for AI coding agents. It parses every symbol in your repository into compact Symbol Cards, stores them in a graph database, and exposes 35 MCP tools so agents can query precisely what they need — without reading entire files.

Quick Start

Install SDL-MCP, index your repo, and connect your first coding agent in under 5 minutes.

Client Setup

Connect Claude Code, Cursor, Windsurf, Gemini CLI, OpenCode, or any MCP client.

Core Concepts

Understand the Iris Gate Ladder, Symbol Cards, Graph Slicing, and Delta analysis.

MCP Tools Reference

Full reference for all 35 MCP tools with parameters and response shapes.

Why SDL-MCP?

Every time an AI coding agent reads a file to answer a question, it consumes thousands of tokens — most of which are irrelevant. A debugging session touching 20 files can burn 40,000+ tokens on context gathering alone. SDL-MCP fixes this with a four-rung Iris Gate Ladder that lets agents dial their context aperture from a pinhole to wide-open:
RungWhat the Agent SeesToken CostTypical Use
1 — Symbol CardName, signature, summary, dependencies, metrics~100”What does this function do?“
2 — Skeleton IRSignatures + control flow, bodies elided~300”What’s the shape of this class?“
3 — Hot-Path ExcerptLines matching specific identifiers + context~600”Where is this.cache initialized?“
4 — Raw Code WindowFull source (policy-gated, justification required)~2,000”I need to rewrite this error handler”
Most questions are answered at Rungs 1–2 without ever reading raw code. That’s where the token savings come from.

Key capabilities

Symbol Cards

~100-token metadata records for every function, class, interface, and type — with confidence-scored dependency edges.

Graph Slicing

BFS over the dependency graph with weighted edges and token budgets. Returns the most relevant symbols for any task.

Delta & Blast Radius

Semantic diffs showing what a change means and which dependents are at risk — not just what lines changed.

Live Indexing

Editor buffer changes are reflected in search and cards in real time — no manual re-index needed.

Development Memories

Cross-session knowledge persisted to both a graph database and checked-in markdown files.

Sandboxed Runtime

Run tests, linters, and scripts through SDL-MCP’s governance layer with executable allowlisting and CWD jailing.

Get started in 3 steps

1

Install SDL-MCP

npm install -g sdl-mcp
2

Initialize and index your repo

sdl-mcp init -y --auto-index
This creates a config file, detects languages, indexes your codebase, and runs health checks.
3

Start the MCP server

sdl-mcp serve --stdio
Point your MCP client at the server. Your agent now has access to all 35 SDL-MCP tools.
Using npx? Replace sdl-mcp with npx --yes sdl-mcp@latest in all commands.

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